The Challenger
by thecontinuer
Summary: What happens when someone comes around that powerful enough to trade blows with Saitama? An unstoppable force meets and immovable object in a battle that will be so epic that words cant describe it.
1. Chapter 1

This is a nonprofit fan based story (fan fiction), ONE PUNCH MAN and all its OVA's and manga are all owned by ONE, Studio Mad House, and everyone else that was involved in its development. Please support the official release for without this story wouldn't exist

Author's note: hello, I just wanted to clarify that this story has a similar premise to a certain arc in the show, unintentionally. I wrote this when the SeaKing arc started and it took until now to finish it due life bombarding me with things I have to do such as exams and what not. So I had absolutely no idea that I was writing something exceedingly similar to a certain arc in the show, I just followed the basic formula that is used during a fight scene in one punch man and lengthen it. Anyway that be all, don't forget to review.

 **The Challenger**

In the Z city ghost town a mysterious hooded man is seen walking through the streets, seemingly in search of something. The ghost town is an extremely dangerous place that has become over run with Monsters. Any sane man would turn tail and leave but he seemed to be casually strolling along and ignoring the numerous warning signs plastered all over the area. As he was walking he abruptly stopped and said: "Damn, what street does he live on again?" He then took a looked at a piece of paper that had an address on it. As he kept walking, numerous piles of dead monsters can be seen scattered all over the road behind him, along with the complete devastation of large buildings and overpasses. The absolute destruction looked as if it was caused by a category 5 hurricane.

 **After a few more minutes of walking he finally came across Saitama's apartment building.**

"So this is where he lives?" He said confused.

"Honestly I was expecting a castle." The mysterious stranger remarked right before he made his way up into the building.

The mysterious man eventually made it to Saitama's front door and proceeded to knock on it. Inside the apartment Saitama was in his pajamas and watching tv when he heard the knocking. He then told Genos to answer the door.

"They Genos could you get that?" Saitama said, however, Genos didn't reply because at this time he was busy cleaning the bathroom.

The knocks got more and more persistent and Saitama eventually decided to see who was bothering him so early in the morning.

Saitama then opened the door and said: "What do you want?" addressing the person in front of him in an uninterested tone.

The mysterious man then pulled down his hood to reveal that he was of Greek decent he appeared to be in his mid thirties. The man had blood red hair, a short beard, brown eyes, a muscular athletic build and was wearing a grey sleeveless hoody, black jeans, and combat boots. He was also carrying a gym bag on his right shoulder

"Good morning, Im looking for a Mr. Saitama, Is he around?" The man said.

"I am Saitama."

"Oh? Well allow me to introduce myself my name is Atlas and I've journeyed across many….." At this time Saitama wasn't really paying Atlas much, he was instead concerned about what to eat for lunch when suddenly he spots Atlas's gym bag.

" _Oh no, this is one of those guys who goes door to door selling useless crap isn't it? The kind of people who will never leave you alone unless you buy their stuff. I got to get rid of this guy!"_ Saitama distressingly thought to himself. Saitama then cut him off by putting his hand in front of Atlas.

"Look whatever it is your selling I'm not interested." Saitama said right before he closed the door.

"Well that was rude, he didn't even let me finish." Atlas said with a baffled expression.

"Guess we'll have to do this the old fashion way." Atlas stated, He then proceeds to cock back his left arm.

On the other side of the door a relieved Saitama turns around and starts heading for his TV when suddenly he senses something.

At that moment Atlas threw a punch right through the door! However, Saitama was able to intercept it with ease. Saitama stopping Atlas's punch in midflight resulted in a massive shockwave that blew apart the other half of the apartment building along with the other buildings across the street.

Suddenly Genos comes out of the bathroom with both his arms locked, loaded, and aimed at Atlas!

"Saitama sensei! Who is this man? Is he a threat because I will incinerate him!" Genos said. Saitama didn't reply instead he was looking down at the ground and processing what had happened.

"WHAT THE HELL YOU JERK! You blew up half of my apartment! You better pay for it! Saitama yelled enraged."

"Well you started it, I mean closing a door on someone before they finished talking was very rude you know. '' Atlas retorted.

"Oh, well if you put it that way then I guess I am to blame. I just thought you were one of those door to door salesmen, my bad" Saitama said after realizing his error.

Atlas then took a look at the damage he caused and said: "Don't worry about the damage il cover it, consider this a down payment." He then took a large wad of cash out of his gym bag.

"So what was the reason you were looking for me?" Saitama asked

"Since you apparently don't like long descriptions il keep it short. My name is Atlas and my dream is to become the strongest in all existence, it just so happens that you're standing in my way. In other words IM HERE TO CHALLENGE YOU TO A FIGHT!" Atlas explained.

Shocked at what he had heard Genos thinks to himself: _"Challenge master to a fight? This individual must be capable of extraordinary feats if he thinks he can stand against Saitama sensei."_


	2. Chapter 2

"You want to fight me?" Saitama asked as he pointed to himself.

"Yes I wish to test my strength against you. Will you accept my challenge?" Atlas asked with a gleam in his eye, exited for Saitama to say yes.

"Hmm sorry but not today" Saitama replied.

"WHAT WHY?" Atlas asked, shocked and disappointed that Saitama didn't want to fight.

"Look, normally id jump at the chance but there's a 90% off sale in the market today and that kind of deal is too good to pass up." Saitama replied.

Atlas just stood there slacked jawed, trying to process what he just heard. As he was trying to decide whether Saitama was an extremely courageous individual for declining the offer or a bumbling dufoos for literally squandering the opportunity, he suddenly got an idea. Atlas then stared to develop devilish grin on his face. It was almost as if he knew what to say in order to convince Saitama.

"Don't you get bored Saitama? You have all that power and yet you never get to use it. Well now's your chance." Atlas said confidently.

"Well you do have a point, but then again 20 yen per cabbage is a steal." Saitama replied.

At this point Atlas was getting really annoyed. He then took a deep breath pinched the bridge of his nose and tried his best not to punch Saitama.

"Alright Alright, How about Il just pay for your food for the month? You see this bag I'm carrying; I filled it up with cash before I came just in case I had to pay off property damage. It's all yours if you just FIGHT ME!" Atlas said frustrated

 **Suddenly Genos intervened.**

"Master Saitama said no. Think it would be in your best interest to leave." Genos said threateningly as his arms started to transform and glow bright yellow. He was just about to attack but Saitama grabbed his shoulder and stopped him.

"Hold on Genos." Saitama said right before he started pondering what to do. _"This atlas guy seems to be pretty strong and there's no doubt he'd put up a fight but I don't wanna take his money."_ Saitama thought to himself. He then started scratching his chin as his decision making got more perplexing.

" _Then again if he gives me the money il finally be able to afford that expensive hair re-growth treatment."_ Saitama thought as he imagined having a full head of hair once more.

After a few minutes of silence Saitama said: "Alright il fight you."

Suddenly his face had changed from a completely innocent look to a serious and intense one. "But only on two conditions. 1, you will only give me a small amount of money, just enough to compensate me for the groceries I could have bought. 2, you better last more than 5 minutes against me in a fight."

"Yes yes of course!" Atlas shouted excitedly.

"So, where are we going to have our battle?" Saitama asked curiously.

Suddenly Atlas's demeanor had changed from exited to serious. "If we go all out this planet will won't be able to handle the power we can generate. But I know of a place that can." Atlas said right before he pulled out a remote from his pocket and with a click of a button a large portal opened right in front of them.

"Wow cool" Saitama remarked at the large swirling void that was composed of an array of colors going in both clockwise and counter clock wise direction.

"Don't be scared it's just a universal shortcut. Come on let's get a move on." Atlas said right before he started walking towards the portal. He then said: "Bring the cyborg along, I want him to witness the fight of the millennium." Atlas then stepped into the portal and waited for Saitama and Genos to pass through.

Saitama then turned to Genos and asked him: "So Genos are you coming along?" At this time Genos was still busy having an internal monologue about what this situation might bring up.

" _This could be my chance to finally see Master at full power."_ He thought to himself right before he said: "Yes I will go with you Sensei."

"I told you to stop calling me that." Saitama said a little bit irritated. The two then started walking into the portal but before they passed all the way through, Saitama remembered that he was wearing his pajamas.

"Hold on, let me get dressed first." Saitama said as he rushed to find and put on his super suit.

After putting on his hard to miss yellow hero uniform Saitama said: "Alright, let's go." He and Genos then went into the portal. As they stepped through they were greeted by world made of green Diamonds. The place had had a blue sky and crystal rock formation all over the place. Suddenly Atlas turned around and explained to them where they were.

"Welcome to the planet Krystalos, a completely uninhabited place with nothing important for us to break." Atlas said right before he unexpectedly stomped a hole into the ground. Then suddenly the crystal ground started to repair itself and reform to look as if nothing happened to it.

"As you can see, Krystalos fixes itself." Atlas said with a smile.

"This is place is so shiny, who'd you find it?" Saitama asked curiously as he looked around.

"I stumbled upon it during my travels searching for worthy opponents across the different universes." Atlas explained.

"I see, so should we begin our fight?" Saitama asked.

"Most definitely" Atlas replied.

The two of them then assumed their respective fighting stances while Genos blasted off to a safe distance to observe the fight.


	3. Chapter 3

This is it! The stage is set and the combatants are ready. On the left we have Saitama the Caped baldy, a man whose power exceeds that of a God and on the right we have the challenger Atlas, a mysterious man who aspires to become the strongest in all known reality.

As the two fighters stood and waited for each other's next move, Atlas suddenly started chuckling.

"How rude of me, the first hit should always go to the guest." Atlas said right before he leaned forward and offered Saitama the chance to punch him in the face.

"Ok" Saitama replied. Saitama then cocked back his arm and threw a normal punch. As Saitama's fist was about to hit Atlas's face, he quickly grabbed Saitama by the wrist and elbowed him in the gut. Atlas hit Saitama with such force that the impact displaced a lot of air creating a sonic shockwave which sent Saitama flying backwards at mach 3.

 **Genos who was observing the fight was dumbfounded by what he just saw.**

"I-Impossible, no one has ever been able to intercept a punch from sensei! Whoever this man is, he might actually put up a fight against master Saitama." Genos commented.

At this time, Atlas watched on as Saitama was hurdling through the air, "il be damned if I let him get the first shot." he said with a smirk. He then braced himself and leaped into the air with such immense power that it caused the diamond ground to break apart, leaving a giant crater where he once stood.

Saitama finally came to a stop as he hit a large crystal mountain and in doing so left a large gaping hole in it. Atlas had just recently caught up with Saitama as he landed a few feet in front of him. Saitama then proceeded to get out of the hole and brush off the debris on his super suit.

"That's the hardest anyone has ever hit me. Are you by any chance a hero too?" Saitama asked with a serious face.

"Me? No, I just fight Monsters." Atlas replied nonchalantly.

Amused at Atlas's answer, Saitama smirked and with a serious face bolted forward with such speed that he completely disappeared from view!

Atlas was caught off guard by Saitama's speed. He took a few steps back and tried to find out where the bald hero might be. _"Damn, he's quick"_ Atlas thought to himself as his eyes darted across the area while looking for this opponent. Suddenly Saitama appeared and threw a strong punch at Atlas! However, it didn't hit its intended target. Atlas somehow managed to block it with the tip of his right elbow and reinforced it by pushing against his right fist his other hand. The force of Saitama's punch was so great that the ground cracked under the pressure and Atlas's feet sunk down up to his ankles. Atlas then tried to retaliate by throwing an upper cut at Saitama but the hero for fun dodged it effortlessly as he jumped back a few feet and face Atlas.

"So you are as strong as they say you are." Atlas said as he took his buried feet out of the ground.

"You're pretty strong too" Saitama replied.

"Too bad only one of us can be the strongest!" Atlas yelled right before he went on the offensive. Atlas bolted toward Saitama and proceeded to throw a flurry of punches and kicks at him but Saitama was able to dodge all of them.

"What's the matter chrome dome? What aren't you fighting back?" Atlas said insultingly as he tried to land a blow on Saitama.

Irritated by Atlas's insult, Saitama got serious and punched him on the jaw. Saitama hit Atlas so hard that there was flash of light followed by a loud boom then everything went silent. Staggered from the force of Saitama's punch, Atlas had trouble finding his footing as he was clearly shook up and dazed.

"Such power! Even after that he is still standing." Genos exclaimed after seeing Atlas with stand a direct hit from Saitama.

With blurry vision clearing up and the ringing in his ears fading, Atlas started to regain his composure. When he finally managed to stand straight he yelled: "Now that's what I'm talking about!" ecstatic that Saitama landed a blow.

 **Atlas then took a good long look at Saitama and his enthusiasm slowly started to fade.**

"That was awesome; No one has ever survived any of my strong punches." Saitama complemented.

"Cut the crap Saitama! Why were you holding back?" Atlas said angrily.

"Because you were holding back as well" Saitama replied with a smirk.

"Was I that obvious?" Atlas asked amused.

"Pretty much" Saitama replied.

"HAHAHAHA! Man the legends spoken about you don't do you justice." Atlas stated.

"Well now that the cats out of the bag, why don't we go all out and have a little unrestrained fun?" Atlas proposed.

"Good idea, I have a new move that I've been working on and I'd love to test it out." Saitama said with a serious face.

"Haha, now that's the spirit. You can go ahead and transform into your ultimate form now." Atlas stated.

Saitama replied by nodding his head, he then assumed a wide fighting stance. Atlas was confused by this and asked: "Is that it, No transformation or anything?"

"Nope" Saitama replied.

"Huh, well thats a first, Anyway it's my turn." Atlas said confidently


	4. Chapter 4

Suddenly the ground shook as Atlas stood tense, his body straining to cope with the sudden burst of energy flowing through him. The ground around him broke into chunks and flew through the air as he is surrounded by a storm of purple lightning.

"T-That power it's UNREAL!" Genos said as he sensed the near infinite level of energy Atlas was generating while he transformed.

As every fiber of Atlas's body seemed ready to burst at the seams. He let out mighty scream which was followed a blinding white light. The light then dissipates to reveal, Atlas with hair as a flaming inferno and his irises glowing bright red.

"That's a lot of energy." Saitama said eager to see how powerful his opponent will become.

"I am Atlas, God of Rage!" the flame haired man yelled.

The two then leaped towards each other and proceeded with the second bout of their fight. Saitama and Atlas then started slugging it out with such force that each punch would heat up the atmosphere and induce lighting storms. As they traded blows the ground surrounding them started being pushed back and shockwaves emanating from their strikes were destroying the crystal spires that were abundant in the area.

"So this is what master is capable of" Genos thought to himself amazed as he witnessed the 2 Gods tear at each other.

For a while the two power houses were on equal footing as each of their punches and kicks canceled each other out. So Atlas decided to change it up by grabbing Saitama's head and slamming it into the ground! The effect of this was immense as Saitama started barreling through the crystal. Atlas then leaped into the air and proceeded to perform an elbow drop on Saitama. Atlas fell with such speed that his whole body caught fire. "Heavenly Bullet!" Atlas yelled, naming his attack right before it hit Saitama. The impact of the move caused a massive explosion that decimated everything in the surrounding area; not even all the earth's nuclear arms would be able to replicate such a destructive onslaught.

"MASTER!" Genos shouted fearing for the safety of his sensei.

As the crystal dust around the area stared to settle, Atlas jumps out of the canyon created by his attack.

"That should have done it, no one has ever survived that attack." Atlas said sure of his victory.

Suddenly Saitama started walking out of the hole.

"H-How is this possible!" Atlas yelled enraged.

Saitama just stared at Atlas until he noticed a tare in the midsection of his super suit.

"Oh man, this was gift." Saitama said dismayed. He then shot Atlas an intimidating stare and said: "You'll pay for what you did to it."

Atlas at this point was still infuriated that Saitama didn't go down. "I will NOT lose to you! ive worked too long and too hard for this! When this ends you will KNEEL before me! Atlas shouted.

"You talk too much" Saitama replied with a serious face

Saitama then went on the offensive as he ran towards Atlas and started throwing punches at him. Atlas was doing his best to dodge Saitama's blows but he was having difficulty keeping up with the bald hero, _"he's too fast I won't be able to dodge him for long"_ Atlas thought to himself. Then suddenly out of the blue Saitama landed a hit on his abdomen. The pain was intense, as Atlas's eyes started rolling back into his skull and blood shot out of his mouth and nose. The self proclaimed God of rage tried to catch a breath and recover but before he could Saitama followed up his last attack with his super move!

深刻な打撃

Serious Strike

The Saitama's punch hit its mark and sent Atlas flying through 6 mountains made out of solid diamond. The back lash of Atlas's body traveling with such energy caused a giant crevasse to form under him as he flew through the air. In addition the debris from the mountains he smashed through were being pulled towards him, almost as if he along with millions of tons of diamonds were being sucked into a black hole.

Eventually Atlas's inertia started fading and he came to a stop as he hit a 7th diamond mountain. However, Atlas's agony didn't end there as the tons of debris following him started crashing into him. This causes the mountain he was stuck on to crumble and fall to the ground.

Now buried under an insurmountable amount of ruble, Atlas could feel his soul as it started to leave his body. His flaming hair slowly started dissipating and reverting back to its original blood red form and his glowing red eyes were getting dimmer and dimmer, this surely seemed to be the end for him.

Suddenly, Atlas hears a disembodied female voice call out to him. "Arthur" it whispered.

"That voice" Atlas said as the speaker's familiarity causes him to relive a part of his past

In the flash back, Atlas stands behind a scrawny and sickly looking child who was sitting on a swing set and sobbing. Without warning the sad scene suddenly changes into one of horror as 2 people one man and one woman are being forcefully separated by a gang of thugs.

"Arthur!" the woman cried out.

"No no no!" Atlas yelled as he leaped in to try and save her but to his disbelief the woman slipped right through him, he knew at that moment there was nothing he could do.

 **While this was happening Saitama was just standing around with his fist still smoking from the power of his serious strike.**

"I might have hit him too hard" Saitama said. At this time Genos who was recording the fight in order to gather data said: "it's finally over, Master has won yet again."

 **Back to Atlas**

The horror continued as his memories started to get shuffled around in rapid succession. This caused him to have a mental over load while the memories moved faster and faster. Atlas couldn't take much more and quickly cover his ears and closed his eyes, wishing it would all stop. Suddenly a loud gunshot rang out! This caused Atlas to be jolted awake.

"IL NEVER BE THAT WEAK AGAIN!" he screamed enraged as he busted through the ruble that was crushing him. In the midst of his fury, Atlas's hair ignited once more, however, it didn't stop there as the inferno started spreading while his hair grew to waist length. The God of rage's eyes also changed as this time around both his ocular orbs glowed bright red and red smoke started to emanate from them.

Atlas noticed that Saitama's serious strike had left a permanent fist shaped indentation on his skin. He then shot a menacing glance started to slowly point his finger at Saitama, "This is the end for you, hero!" he yelled right before he started charging up his attack. As the power built up around him the very planet of Krystalos started to shake and the surface started to crack apart, forming deep crevasse and ravines in the process. Then suddenly the blue sky above them started shifting to a red hue and massive bolts of lightning started raining down, destroying more of the once beautiful diamond landscape.

Genos watched on in horror as the planet shook more violently, he feared that the planet they were on was about to explode at any second.

Now, having built up enough energy, Atlas proceeded to place his palms on the ground. He then buried his finger deep into the diamond crust and yelled:

Finishing move!

Crimson Tide

Atlas released every ounce of built up energy he had into the ground! And a massive red tidal wave of radiating energy about 3 miles across sprung out of the diamond crust and headed straight for Saitama. As the nuclear tsunami moved forward it also brought along the layer of crust beneath it.

Saitama watched on as certain doom was headed towards him, however, he was not afraid, in fact quite the opposite, he was exited. For so long he hoped to find a challenging opponent and now he finally got his wish.

"Bring it on" Saitama said confidently.

The wave then enveloped the bald hero, along with 3 miles of terrain! Suddenly, the energy wave started shrinking and condensing into a crimson orb. The orb then started to solidify and levitate 50 ft into the air. Inside, millions of explosions started firing off in rapid succession. On the outside the eruptions only seemed to be the size same as a car bomb but in reality each explosions has the equivalent power of 1000 suns exploding at the same time.


	5. Chapter 5

10 minutes have passed since Saitama was engulfed by Atlas's crimson tide and all hope seemed lost. Genos sat there in turmoil still unable to accept the fact that his master could be dead.

Suddenly a loud thud can he heard coming from the inside of the orb.

Another thud followed and the sphere started cracking

On the third heavy clunk the entire orb shattered into pieces freeing Saitama!

Saitama fell to the ground on his knees with his super suit torn to bits, only leaving him in his shorts; He was also covered in scrapes, scratches, cuts, and bruises. After taking a few deep breaths, the exhausted Saitama slowly started to get on his feet.

"Now I'm pissed" he said with an enraged look on his face.

Without warning he ran towards Atlas with all the speed he could muster, tearing through the ground as he ran. Within a mere second he was right in front of Atlas. Saitama then cocked back his right arm, getting ready to unleash his most powerful strike!

深刻シリーズ - 究極の終わり

Serious Series - Ultimate End

 **Not willing to lose the fight Atlas retaliated with his own super move!**

Elbow Breaker!

The two strikes's clashed and created an immensely powerful pulse wave, so powerful in fact that something unforeseeable started to happen.

Genos watched on as tares and holes started to appear throughout the sky where the pulse wave had passed through. The tares looked to be windows and vortexes into other locations. You could see the beings on the other side flee in terror as they too were afraid of the various dimensional pockets that were sprouting up and quickly increasing in number. Suddenly, EVERYTHING! Started to shake violently as the back lash from Saitama's and Atlas's strikes could be felt throughout all of creation!

"MASTER STOP YOUR DESTROYING THE UNVERSE!" Genos yelled at the top his lungs as the universe itself starts to break apart!

However, Genos's pleas fell on deaf ears as Saitama and Atlas kept pushing at each other with Saitama clearly gaining the upper hand. Atlas just wouldn't give, so he pushed back Saitama's Ultimate end with every fiber of his being. However, this was not enough as Atlas's body couldn't handle the strain any longer and his entire right arm BURST APPART INTO A MILLION PIECES!

Clearly defeated, Atlas flaming hear and red eyes dissipated instantly powering him down. He then fell to the ground on his knees and tears started to run down his face and he started to whimper.

"It's not fair! I worked so hard for so many years to become the best but I was so easily defeated by you!" Atlas ranted as he punched the ground repeatedly with his remaining arm.

As Atlas laid face first on the ground in denial, Saitama suddenly extends his hand to him and with a smile on his face says: "Great fight"

Atlas looked up at Saitama in shock that a warrior with such power could be so generous and humble.

"I get it now, I was a fool to have challenged you in the first place. There is no surpassing a being that has no limitations." Atlas said

Atlas then wiped off his tears and took Saitama's hand. The hero fun then proceeds to help his defeated opponent up on to his feet.

"Well it's either that or il have to shave my head." Atlas remarked. Saitama then shot him a menacing stare to which Atlas nervously replied: "Just kidding, the bald look suites you fine. Please don't punch me again." Saitama then smiled as his face return to its normal unassuming guise.

"Hey Genos could you give me a hand!" Saitama called out. Genos then blasted off towards his Sensei and helped carry the injured Atlas as soon as he arrived.

As the three men walked towards the exit portal, Atlas glance at Genos's shiny metal arms and said: "hey cyborg, I never got your name."

"It's Genos"

"Nice to meat you, Im Atlas"

"Do you happen know a place where I could get one of those fancy metal arms? As you can see I'm sort of missing something important." The one armed man asked.

As the heroes pass through the portal they leave the planet Krystalos as a desolate wasteland with broken diamond and large scars on its surface. Suddenly, the planet does what it does best and starts to re-grow itself, leaving no trace of the greatest battle that has ever been fought.

 **The End**

 **POST CREDIT SCENE**

A day after the universe greatest battle had ended; the world was pretty much in ruin due Atlas and Saitama's universe breaking fight. Not many people died, however the property damages were immense.

the trio had a long hard day of helping the citizens of Z city in cleaning up the mess they made so they decided to grab a bite to eat and thus visited a noodle shop and ordered take out. Everything was well and good, Atlas even got a shiny new Cybernetic arm thanks to Genos. He also customized his appendage by painting hot rod flames on it. The three then made their way to Saitama's apartment to eat.

After 30 minutes of hardy eating the hero's felt satisfied. Saitama, who was feeling lazy didn't really want to clean up.

"Hey guys, could you clean this up after you're done?" Saitama asked the two

"Yes Sensei" Genos and Atlas replied in unison.

"Oh great, there two of them now" Saitama said regretfully.

 **Author's note:** thanks' ever so much for reading my work. By the way, my friend is working on a more artistic novel like version of this story. Would you guys like to read it or not?, Please let me know. Don't forget to review


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